If I do not switch on the 12 VDC power to the tuner, is the tuner always in the bypass position so that the RF goes right through it and nothing is tuned?
At any time12V is not applied to the tuner, you will have total inductance 16 mH (microhenry), in series with your antenna. To bypass the tuner you must:
A) Have 12V applied. Note: If you have 12V applied then coupler would be on - If no TXMT occurred, it would be in bypass mode.
B) Reset the tuner by turning 12VDC off then on or use the Reset button on the Smartlock.

Can coax cable be attached to the SG-239 antenna output?
Yes, coaxial cable can be used on the output of the SG-239. This lead should be as short as possible. However, we recommend this alternative only as a last resort or special application as it may compromise your radiation efficiency.

It says in the manual that when changing frequency the tuner will check and re-tune when needed. Does the unit have a frequency counter in it?
Yes, there is a frequency counter built-in which is the heart of the memory bin sequencing.

Is there any way to find out how many of the 170 memory bins are programmed and which memory bins are being used?
No, transmit memory bins are directly related to the transmit frequency. They are arranged to cover all frequencies from 1.8 to 30 MHz.

On manual tuning in transmit, the manual says use S3 thru S8 to tune the SG-239. Is this just pressing these buttons in a random sequence? Without a SWR meter how does one know the tuner is set correctly? Is there any preference on how to do this?
If no VSWR meter is available, you should perform receive tuning to get a close tune. Start with no tuning elements engaged. For transmit tuning, you will need a VSWR meter.

Receive-Mode Steps (The following two steps should be sufficient.)
A) Tune coil up for maximum receive signal or noise level.
B) Tune input capacitance up for maximum receive signal or noise level.

What do the LEDs represent?
The LEDs represent the current status of the tuner/antenna match. Displayed is impedance, reactance, VSWR, RF applied, and tuned condition. As the tuner goes through its tuning process, these indicators are updated. Exact descriptions of each LED are here.

Fine tuning is done with S3 thru S8 but how does one know the tuning has improved?
Improvement can be checked with an external VSWR meter or radio equipped with a VSWR meter.

Do you have a waterproof version of the SG-239?
If you are looking for an inexpensive waterproof Smartuner, we recommend moving up to the SG-237. It is waterproof with more frequency ranges for a specific antenna and more tuning steps - 1/2 million compared to 1/8 million on the SG-239. Visit the SG-237 page to find out more on the SG-237.